Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 14: Poster: Two-Dimenaional Materials and Topological Insulators
HL 14.10: Poster
Monday, March 20, 2017, 14:00–18:00, P2-OG3
Transport measurements in high mobility hBN-graphene-WS2 stacks — •Tobias Rockinger1, Tobias Völkl1, Martin Drienovsky1, Kenji Watanabe2, Takashi Taniguchi2, Dieter Weiss1, and Jonathan Eroms1 — 1Institute of Experimental and Applied Physics, University of Regensburg, D-93053 Regensburg — 2National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
To induce spin-orbit coupling in graphene, heterostructures of graphene and tungsten disulfide (WS2) are investigated. To achieve high mobilities, we encapsulated graphene between hexagonal boron nitride (hBN) and WS2 via the van der Waals pickup method. Using Cr/Au edge contacts it is possible to achieve reliable, low resistance contacts. In this way we obtained carrier mobilities in graphene between 30.000 cm2/Vs and 116.000 cm2/Vs. We observed Shubnikov-de Haas oscillations in graphene sandwiched in between WS2 and hBN. While searching for weak localization and weak antilocalization we get results which are dominated by other effects. It seems that due to the small (0,8 µ m) width of the hall bar geometry, propagation of electrons through the structure is mainly influenced by sample edges and ballistic effects. This leads to a peak in the magnetoresistance around 100 mT. With this value we calculated a cyclotron radius of 0,8 µ m and an effective sample width of 0,4 µ m which equates 50 percent of the measured width.